The head of Yum Brands Inc.'s China operations made a rare appearance to take aim at the country's food-safety issues and win back customers after allegations of quality oversights at the company's KFC restaurants caused consumer confidence and sales to tumble in its largest market.

Yum is aiming to prevent food-safety problems by cutting its ties with suppliers that source their chicken from small farms that are hard to regulate, said Sam Su, the chairman and chief executive of Yum's China division, in a press briefing Monday. But the fundamental problems that sparked consumer concern over the quality of the company's chicken reside in China's meat industry, which relies on small-scale farms and is vulnerable to risk, Mr. Su said.

'We have been in China for many years now, so we can't say that we haven't known this,' said Mr. Su. 'But this situation is very complicated and it cannot be fixed with an apology.'

The public appearance is rare for Mr. Su, who typically keeps a low profile in his position at Yum. But the Louisville, Ky., company is trying to win back customers to its KFC outlets in China after a probe of its chicken supply late last year resulted in a spate of negative publicity that caused sales to tumble. Mr. Su apologized in January for communications missteps in handling public reaction to the probe.

Mr. Su said in an interview that Yum is working with internationalpoultry suppliers to help them enter the Chinese market or to invest in China's domestic suppliers to improve their quality. Yum will have future announcements on bringing additionalpoultry players to the market, Mr. Su said, declining to comment further.

For Yum, China is a critical market that accounted for 42% of the company's profits last year. Yet the company's fourth-quarter same-store sales in the country fell 6%, a deeper fall than its previousestimate of a 4% decline, as consumers in China pulled away from its KFC chain after discovering that food-safety authorities were looking into whether KFC purchased raw chicken with higher-than-permitted levels of antibiotics from two of its poultry suppliers.

Yum attempted in December to manage customer concerns with statements on its official Sina Corp. Weibo microblog, a service similar to Twitter. Still, word-of-mouth spiraled, leading to thousands of negative comments and would-be KFC consumers who steered clear of the chain.

Sales at its KFC stores open at least 12 months in China declined 41% in January, according to company statements.

Yum invited representatives from industry groups such as the China Chain Store & Franchise Association, the China Cuisine Association and the China Animal Agriculture Association to speak at the company's press briefing and bolster the claim that China's food sector requires more investment and more management to ensure quality and consumer safety.

The food industry in general in China faces greater need for safeguarding, Mr. Su said, adding, 'It's not something that Yum alone can do.'

In late December, Shanghai's food-safety regulator said it was investigating whether Yum responded appropriately to test results that had shown eight out of 19 batches of chicken samples Yum sent to labs for testing in 2010 and 2011 had higher than acceptable levels of antibiotics.

A spokesman for Yum said as soon as the company learned of the Shanghai watchdog's test results, it immediately contacted restaurants, removed the chicken from outlets and destroyed it.

Shanghai's food-safety watchdog in January said suppliers were to blame for antibiotics issues, but that KFC needs to increase its oversight of poultry suppliers.

Mr. Su said he doesn't feel that Yum was unfairly blamed for problems in China. 'Customers do expect us to safeguard our food,' he said, adding that Yum and other foreign companies have been known for and high standards and that people and regulators hold them to those standards.

Recent incidents won't affect the company's plans for China growth, Mr. Su said.

Yum aims to open 700 stores in China this year. It already operates more than 4,000 KFC outlets and more than 700 Pizza Huts in the world's most populous country.

KFC plans to minimize its risk in China by boosting supplier testing and will work only with those that have direct management over their chicken houses, Mr. Su said, adding that the chain cut from its network more than 1,000 small poultry producers used by the company's 25 poultry suppliers.

Food safety has been a major issue in China over the past decade, as agriculturalreform has lagged behind industry expansion. Most of China's agrarian landscape is made up of small-scale farms, using different feed and varied animal breeds. That adds steps to the distribution channel, maximizing the chances of contamination and decreasing accountability.

The dairy industry has been pushing to consolidate dairy farms after a 2008 milk scandal resulted in the death of six infants and illnesses in 300,000 others, highlighting problems with accountability of smaller farms.

Mr. Su said that Yum's challenges go beyond food safety in China, as it was clear before the recent chicken probe that sales would not meet targets set for the year. 'The previous year, we were firing all cylinders with breakfast, lunch, dinner, afternoon and 24-hour sales and we underestimated our ability to lap ourselves' Mr. Su said.

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